Telephone



(NoMoae'l.)

D. DRAW-BAUGH.

TELEPHONE. y

No. 290,978. Patented Deo. 25, 1883.

INVENTOR' dd/M A' 7 ATTORNEY;

UNITED STATES PATENT Ormea.

DANIEL DRAWBAUGH, OF EBERLYS MILL, PENNSYLVANIA.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 290,978, dated December25, 1883.

` Application filed June 20,1883. (No model.)

To @ZZ whom it may concern,.-

Be it known that I, DANIEL DRAwnAUem of Eberlys Mill, Cumberland county,Pennsylvania, have invented new and useful Improvements in Telephones,of which the following is aspecication.

The invention relates to a magneto-telephone ofthe class commonly usedas receiving-instruments; and it consists in the construction herein setforth, whereby one of the polepieccs of the permanent magnet constitutesthe core of the electro-magnet. The other pole-piece of oppositepolarity is substantially in the form ofa cylinder encircling theelectro-magnet, the coil of which is rigidly iixed between saidpole-pieces. The diaphragm is of inductive material, and is notpolarized. This construction I have found materially conduces toloudness of sound emitted and clearness oi' articulation.

In the accompanying drawings, Figure 1 is a face view of the instrumentwith the mouthpiece removed and part vof the diaphragm broken away. Fig.2 is a vertical section on the linea,` x of Fig. 1. Fig. 3 is atransverse section on the line y y of Fig. 1. Fig. 4 shows thecylindrical pole-piece detached.

Similar letters of reference indicate like parts.

A is the body of the instrument; B, the mouth-piece; C, a diaphragm ofinductive materia.,secured between said mouthpiece B and bodyr A, andhaving interposed between its -rear side and the body a gasket orwasher, D,

of paper or rubber.

E is the permanent magnet, secured to the body by the screws F. One poleof the magnet E terminates in a bar, Gr. Said bar may be formed of thematerial of the magnet itself, and be a prolongation thereof; or it maybe a separate piece, as shown, secured to the magnet by a screw-thread,or in any other convenient Way. The bar G constitutes the core of thehelix or coil of insulated wire H. The spool or bobbin I of this helixhas its rear flange, J, larger than its front liange, K.

L, Fig. 4, is a circularly-curved or substantially cylindrical piece ofinductive metal, which surrounds the coil H and front flange, K, of thespool I, its rear edge abutting against the ilange J of said spool. Aportion of the flange J is cut away to allow of the passage through ofan offset or projection, M, ot' the pole-piece L. Said projection is incontact with one pole of the permanent magnet E on the outside of theinstrument, as shown in Fig. 2. The spool I is thus rigidly held betweenthe pole-piece L, which Inay fit tightly in the body A and the magnet E.By this constructipn both poles of the permanent magnet are presented tothe. diaphragm, and their arrangement is such as to form a magneticfield of considerable intensity. The diaphragm is -not polarized.

I claim as my inventionl. The combination, in a telephone, of anonpolarized diaphragm of inductive material, a permanent magnet havingone of its poles terminating in a bar or core and the other terminatingsubstantially in a ring or cylinder, and a fixed helix carried by thecore and located within the ring or cylinder, spbstantially asdescribed.

2. In a telephone,apermanent magnet forming a handle for the instrument,and carrying at one extremity the core and at the other the tubular orcylindrical extension, in combination with the flanged spool containingthe helix, one of said flanges being itted to and supported within thetubular extension, while the other iiange rests against the end of thelat.` ter, whereby the several parts are fixed and retained in properrelative position for co-operation with the diaphragm, substantially asdescribed.

3. In a telephone, the case A, supporting the diaphragm, the permanentmagnet E, adj ustable core G, and cylindrical extension L, incombination with the spool I, having the flanges K J, as and for thepurpose set I'orth.

DANIEL DBAWBAUGH.

Witnesses:

FRED. M. OTT, M. W. JACOBS.

